We're
into a busy season along the Meso-American Flyway, with many sorts of
birds escaping from the cold northerly climes, some of which are making
their way from Canada's north down to Tierra del Fuego. Most don't
travel that far, and some winter right here.

Particularly impressive are the millions of soaring raptors that pass
through here, circling and soaring high on updrafts, then gliding down
to the next updraft on their way toward points south.

A particularly good place to watch the migration is Ancon Hill, as
winds coming off of the Pacific Ocean hit that hill and are deflected
upward, creating favorable conditions if you are a glider pilot or a
bird. There is also some of that effect where winds come off of the
Pacific and hit tall buildings, as in Punta Paitilla, pictured above.

Most of the raptors that come through here are of one of four
species: broad-winged
hawks, turkey vultures, Swainson’s hawks and Mississippi
kites. The Audubon Society and Birdlife International monitor the
migrations, taking censuses and keeping careful records over the years.
Despite this, there are things that we don't know with much certainty,
such as the precise destination(s) of the turkey vulture migration(s).
The birders who participate in these surveys are the front-line
sentries who detect the effects of bird habitat destruction, and no
doubt they will be among the first people to document how climate
change affects migratory bird habits.

The raptors need to
get through here before dry season kicks in. Blue skies, the absence of
rain and the arrival of masses of tourists may be the things that
people notice the most about the change of seasons, but one of its most
unequivocal natural expressions is a shift in the winds. When the wind starts
blowing steadily out of the north, that's the beginning of dry season.
That also changes the flying conditions for birds, most notably the
locations of the updrafts.